Camshaft adjusting devices of said type are well known in the prior art, wherein reference is made by way of example to DE 10 2005 052 481 A1 and to DE 10 2005 041 393 A1. In the camshaft adjuster there is provided a vane wheel in which vanes are integrally formed or arranged. The vanes are situated in hydraulic chambers formed in an outer rotor. Through corresponding charging of the respective side of the hydraulic chambers with hydraulic fluid, an adjustment of the inner rotor relative to the outer rotor between an “early stop” and a “late stop” can be realized. Here, the flow of hydraulic oil is controlled by means of an electrically actuated directional control valve. The valve has a housing in which is formed a valve bore. A control piston can move in a displacement direction relative to the housing, for which purpose an electromagnetically actuated linear displacement unit is used. During operation of the internal combustion engine, the linear displacement element of the valve is acted on by the vehicle electrical or electronic system with a control current such that—as a function of the engine parameters—a desired camshaft adjustment or adjustment of the gas exchange valves is realized.
To control the movement, therefore, hydraulic fluid is conducted according to demand into the hydraulic chambers by means of the control valve. Here, the pressurized hydraulic oil is conducted by a hydraulic pump into the hydraulic chambers via the cylinder head and via the region of the camshaft bearing via the said fluid channel.
The following fact has proven to be disadvantageous: to produce the fluidic connection between the hydraulic pump and the control valve, according to the prior art, there are formed into the camshaft in the region of the camshaft bearing a turned groove and through bores, via which the pressurized fluid is conducted. Both the turned groove and the bores weaken the camshaft. Furthermore, the formation of the turned groove and through bores is cumbersome and entails corresponding machining costs. Furthermore, in the previous known design, the camshaft must be formed as a solid shaft, which has correspondingly disadvantageous consequences with regard to the weight of the camshaft.